in article , Frank
Dresser at wrote on 3/26/04 2:09 AM:


"Biz WDØHCO" wrote in message
...

This is fun! Well yea about the regen for sure - Some of those Superhets
leaked just as much. (Like a T.O. in a leatherette covered plywood box)


The page I posted on the binaries says the Scott REE was used in the crew's
quarters. Was the well shielded Scott radio provided so crewmen wouldn't be
tempted to bring their own radio on board?

I think at first they were.... until a ham plugged in headphones - pulled
the 6L6 audio power amp tube out with heaters and B+ voltages, got a cap and
wound a coil and had himself a nice little 2 watt transmitter. I can see him
asking the captain where's the best place to hang a 40m dipole. HI HI Of
course, a real spy would simply key the local oscillator to send a ships
position. Throughout the the rest of the war sailors were not allowed
personal radios or tube equipment of any kind. I believe that rule still
applies to this day about personal electronics.

As for the Scott SLR-12B - the typical install was to stack up 6 of them
together tuned to different stations and install squawk boxes with 6
pushbuttons and a vol control throughout the ship. You can select which
audio feed you could listen to but only morale officer decided which
stations to tune.


but think about this... middle of the ocean -
late at night -
100's of miles from anything -
floating around in a sub with everything turned off -

During a war under radio silence with just receivers turned on...

100 miles seems possible to me.



I think "possible" and "iffy" are two ways of saying the same thing from
different viewpoints. I suspect the usual thunderstorm crackle from South
and Central America, the Caribbean, the Mediterranean and Africa would
overwhelm local oscillator radiation from a superhet at much less than 100
miles nearly all the time.

You are right - but we were talking about the North Atlantic sub activity -
45 to 55 deg lat. Very few lightning strikes within this region - it's quiet
most evenings even in the dead of summer. A dead carrier, even a weak one is
easy to find with the BFO just barely audible and the AGC turned off.

All bets are off in the case of a regenerative receiver being used with the
detector's regeneration control turned up into the oscillation region in
order that an anticipated CW signal could be heard more clearly.

The posted page also says the Germans were suspected of being able to listen
in on the 455 kc IF radiation. This would even more tenous than local
oscillator radiation. Again, not impossible, but I doubt long range
detection could be done with any reliability.

You must remember that LF "Huff-Duff" was pretty advanced at the time. LF
airport beacons were the primary form of Aircraft and coastal ship
navigation. (They still exist to this day but I doubt few pilots even know
how to use them.). Almost every ship and plane had one of those funny loop
antennas and if you look at old pictures - you'll see that German subs had
them too. Even though there were very few Nav beacons in Europe during the
war. !!??!!

You might be right about the range but NAVY was concerned enough to give
large RCVR contracts to Scott. The ARMY didn't care and they got Echophone
EC-6's and Halli RE-1 Sky Courier's. GI's could carry (later drag) their own
radios and many did. T.O.s were the most popular with officers. Poor solders
had the "Gillette Blue Blade" special. ;^)

I don't doubt ships were being detected at long range, and using well
shielded receivers was a wise precaution. But I'll speculate that German
code breaking detected at least as many ships as long range direction
finding, and it wasn't immediately obvious to our Navy just what tipped off
the ship's location.

Some Salvagers came across a sunken German Sub just off the New Jersey
coast. Clearly they were parked several miles offshore watching for the
start of a convoy. Somehow they signaled the German High Command which
ordered the wolf pack to form a sub screen (straight line of subs 100 miles
apart) and wait for the convoy to pass. Top speed for those concrete
"Victory" ships was about 6 knots so, for the most part, they were sitting
ducks once spotted.

Historically very little has been written about the bravery of merchant
seamen. If your ship was hit and went down - You would watch convoy ships
pass by because they were under orders not to stop. You would have an hour
or two splashing in the water till the end. If you could find a life boat -
you would be 1500 to 2500 miles or more from land. A slim chance at best.

Long Range Flying boats patrolling the North Atlantic and improved Sonar
technology finally ended the Nazi sub terror.

So you see, there is a little bit of history in every old radio ... :^)



- Biz WDØHCO